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[英]TypeError: 'function' object has no attribute '__getitem__' in python
[英]TypeError: 'function' object has no attribute '__getitem__'/Python
我目前正在使用Python使用rk方法來解決函數。 r8_rkf45是一個文件,有助於繪制函數( http://people.sc.fsu.edu/~jburkardt/py_src/rkf45/rkf45.py )。
import numpy as np
import matplotlib.pyplot as plt
from numpy import zeros, linspace, exp, sqrt
from rkf45 import *
from r8_rkf45 import *
def rungekutta(ode2, x0, t, n):
n = 200
z = zeros(n)
a = zeros(n)
f = ode2
neqn = 1
abserr = sqrt(finfo(double).eps)
relerr = sqrt(finfo(double).eps)
flag = 1
t_start = 0.0
t_stop = 10.0
t_out = t = 0.0
y = np.array([0.0])
yp[t, y] = ode2[t, y]
for i_step in xrange(0, n - 1):
t = ((n - i_step + 1) * t_start + (i_step - 1) * t_stop) / (n)
t_out = ((n - i_step) * t_start + (i_step) * t_stop) / (n)
y, yp, t = r8_rkf45(ode2, neqn, y, yp, t, t_out, relerr, abserr, flag)
z[i_step - 1] = t
a[i_step - 1] = y
def ode2(x0, t):
alpha = -1
xp = -alpha * x0
return xp
def main():
n = 200
c, b = (0.0, 10.0)
x0 = 1.0
t = linspace(c, b, n)
y = np.array([0.0])
yp[t, y] = ode2[t, y]
plt.plot()
result_rungekutta = rungekutta(yp, x0, t, n)
plt.plot(t, result_rungekutta, "r")
plt.xlabel(t)
plt.ylabel(xp)
plt.legend("Runge-Kutta")
plt.show()
if __name__ == "__main__":
main()
但是我仍然得到一個追溯:
Traceback (most recent call last):
File "C:/Python27/idea.py", line 50, in <module>
main()
File "C:/Python27/idea.py", line 40, in main
yp [t,y]= ode2 [t, y]
TypeError: 'function' object has no attribute '__getitem__'
我究竟做錯了什么?
ode2
是一個函數,而不是列表(或具有可通過索引訪問的成員的其他對象)。 嘗試, yp [t,y]= ode2(t, y)
您需要使用()
調用函數:
yp [t,y]= ode2(t, y)
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